Hello, Pulmonary Tuberculosis is active open if your sputum contains the Acid Fast Bacilli( AFB) the causative organism. The test is to examine the early morning sample of sputum for AFB for 3 consecutive days. If there is no sputum , then a morning gastric lavage is examined. An AFB smear may be done in conjunction with a molecular test for TB termed nucleic acid amplification test (NAAT). Both Smear and NAAT are negative then probably the lesion is inactive. Certain countries insist on sputum culutr ff the samples are negative . It takes about 6 to 8 weeks to know the result. In addition indirect tests like a high ESR, a stongly postive Mantaux ( PPD) test are indirect evidence for an active disease. Rules vary from country to country. In Kuwait, you would lose your job if found active. If not active you will be allowed to work with periodical surveillance for activity. I am available to answer further queries if any. Dr. Noble Zachariah If you find the answer helpful, please indicate so to guide others with similar query. Thanks